Dissection of the Arabidopsis thaliana phosphate starvation signalling

International audiencePhosphate (Pi) starvation triggers molecular, physiological and developmental responses aimed for recycling internal Pi, recovering external Pi, trapping metals and limiting growth. When grown on a low-Pi medium, the Arabidopsis root growth is inhibited. By using the Arabidopsis natural variation we have identified LPR1 (At1g23010), and its paralogue LPR2 (At1g71040). They both encode for a multicopper oxidase, the activity of which reduces root growth when seedlings are on a Pi-deficient medium. The LPR1 protein is located in the endoplasmic reticulum and genetically interacts with PDR2, a P5-type ATPase (At5g23630). These results provide strong evidence for the involvement of the endoplasmic reticulum at the root tip in sensing and/or responding to Pi deficiency. In order to get more insights into this pathway, we started new genetics and chemical genetics analyses